青海省大柴旦镇鱼卡金矿成因探讨

发布时间：2018-01-02 21:30

  本文关键词：青海省大柴旦镇鱼卡金矿成因探讨　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

  更多相关文章： 鱼卡金矿 矿床成因 造山型金矿 物质来源 柴北缘

【摘要】：鱼卡金矿床位于柴北缘绿梁山-双口山一带,围岩为滩间山群变碎屑岩。围岩蚀变中硅化、黄铁矿化与金矿化关系最为密切,可作为直接找矿标志。矿石类型以石英脉型为主构造蚀变岩型次之。热液成矿期可分为石英-绿帘石、石英-多金属硫化物、黄铁矿-石英、碳酸盐等四个阶段。矿床整体位于绿梁山大型韧性剪切带偏上盘位置的次级断层中,为韧性-脆性构造转化的部位。整个矿化带和单一矿体,具有北侧脆性变形强烈,南侧韧性变形更强特征,可能指示矿体向南侧伏的规律。流体包裹体均一温度均值为227.23℃,盐度均值5.33%,密度均值0.87 g/cm3,压力均值59.97 MPa。成矿深度均值6.23Km。单矿体由南往北,上述参数具有逐渐变大的趋势,反向论证了矿体向南侧伏特征。包裹体气相成分以富含CO2为主和少量的CH4。成矿流体为中低温、低盐度、低密度、富含CO2流体。氢氧同位素研究表明,主成矿阶段石英的δD值为-58.5‰~-41.6‰,δ18OH2O值5.20~6.01‰,成矿流体主要来自于变质水。矿石黄铁矿硫同位素δ34S变化范围为0.5~7.4‰,均值4.43%,变化相对较大,硫可能主要来自深源的岩浆硫,并不同程度的混入了壳源物质。矿石铅同位素组成为,206Pb/204Pb为18.238~18.62,均值为18.3133,207Pb/204Pb比值为15.59~15.618,均值为15.604,208Pb/204Pb为38.039~38.775,均值为38.1697,相对富集铀铅和略微亏损钍铅。铅μ值为9.45~9.51,ω值为35.64-36.85。在增长曲线图解及构造判别图解上,矿石铅同位素投点落在造山带演化线上、造山带演化线附近以及造山带范围内,矿石铅主要为造山带铅,并不同程度的混合了壳源和幔铅。鱼卡金矿金主要以独立矿物形式存在和固溶体的形式进入载金矿物,矿床载金矿物主要为黄铁矿。矿区辉长岩的成岩年龄为387.5±7.2Ma,且辉长岩普遍发生矿化、蚀变以及韧性变形等,表明金矿化时代晚于辉长岩的侵入时代,辉长岩与金成矿关系不大。鱼卡金矿具有典型造山型金矿的普遍特征,应属于造山型金矿。
[Abstract]:Yuqia gold deposit is located in the northern margin of the Qaidam Basin in Liangshan - green SHUANGKOUSHAN area, the surrounding rock is tanjianshangroup variable clastic rocks. Rock alteration silicification, pyritization and gold mineralization was most closely related, can be used as direct prospecting. The ore types are mainly of quartz vein type tectonic altered rock type. Hydrothermal mineralization period can be divided into quartz epidote, quartz polymetallic sulfide quartz, pyrite, carbonate and so on four stages. The overall deposit is located in the green Liangshan ductile shear zone on the location of the partial secondary faults, for ductile brittle structural transformation of the area. The whole mineralization belt and single ore body, with the North strong brittle deformation, deformation characteristics of the South may indicate a stronger toughness, south side volt orebody rule. The homogenization temperature of fluid inclusions mean of 227.23 degrees, the mean salinity 5.33%, mean density of 0.87 g/cm3, the mean pressure 59.97 MPa. 6.23Km. single ore from the mean depth of mineralization The south to the north, the parameter has gradually become a big trend, south side volt reverse demonstration of orebody characteristics. Gas composition of fluid inclusion in CO2 rich CH4. and a small amount of ore-forming fluids for low temperature, low salinity, low density, CO2 rich fluid. The hydrogen and oxygen isotope studies show that D value is the main metallogenic stage of quartz -58.5% ~-41.6%, 18OH2O values of 5.20~6.01%, the ore-forming fluid mainly from metamorphic water. Ore pyrite sulfur isotope 34S changes in the range of 0.5~7.4%, the average is 4.43%, relatively large changes, sulfur may mainly come from the deep magmatic sulfur source, and to some extent mixed with crustal material. As the Pb isotopic composition of ore. 206Pb/204Pb 18.238~18.62, the mean 18.3133207Pb/204Pb ratio was 15.59~15.618, mean 15.604208Pb/204Pb 38.039~38.775, the average is 38.1697, the relative enrichment of uranium and thorium lead a slight loss of lead. Lead value is 9.45~9.51 values 35.64-36.85. in the growth curve diagram and tectonic discrimination diagrams, ore lead isotope investment fell in the evolution of orogenic belt line, orogenic belt evolution of orogenic belt and near the line within the scope of the ore lead to the orogenic belt lead, and varying degrees of mixed source crust and mantle. Ore lead fish kankin gold mainly in the form of independent minerals the existence and the form of a solid solution into the gold bearing mineral deposits of gold bearing minerals are mainly pyrite mine. Gabbro rock forming age was 387.5 + 7.2Ma, and the widespread occurrence of gabbro mineralization, alteration and ductile deformation, shows that gold mineralization in late age of gabbro intrusion age, gabbro and gold mineralization is not common. The characteristics of gold fish card has the typical orogenic gold deposits, should belong to orogenic type gold deposit.

【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.51
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本文编号：1371003